56 FERTILIZERS 



the many advantages of the cover crop already 

 cited there may be special situations where the 

 water is all necessary to the orchard. If the water 

 right were limited by the capacity of the ditch or if 

 the season's rainfall were too short to risk the loss 

 of water necessary to a cover crop, straw or dam- 

 aged hay could be hauled and spread and plowed 

 under as a fair substitute. Any amount of humus 

 could be added in this way and all of the rainfall con- 

 served for the summer months. 



SUMMER COYER CROPS. 



85. It is difficult to maintain the supply of humus 

 material under conditions of constant irrigation and 

 cultivation. Cover crops have been raised in sum- 

 mer as well as in winter in a few instances. Horse 

 beans and cow peas have been used for the purpose. 

 They are planted in May or June and turned under 

 in August, and while the results are undoubtedly 

 beneficial the extra water necessary will prevent the 

 practice from becoming general. 



The United States Government has found by ex- 

 periment in California orchards, several legumes that 

 promise a greater tonage of green matter, under 

 equal conditions, than the present Oregon or com- 

 mon vetch so generally used. These include two 

 species of Vicia; one pea, and one bean. So that 

 this phase of agriculture will no doubt be improved 

 and modified from time to time. 



The green manure wanted by orange growers is 

 one that will grow quickly as California winters are 

 short and dry, and growers cannot afford to let the 

 ground rest undisturbed very long. 



